Generally, a steering apparatus of a vehicle is designed to change a running direction of the vehicle. The steering apparatus includes an operation mechanism, a gear mechanism, and a link mechanism. The operation mechanism includes a steering column cover which includes a steering wheel that a driver directly handles, a steering shaft engaged with the steering wheel, and a tilting apparatus and telescopic apparatus engaged to a portion of the steering shaft and providing a certain convenience function needed for driving.
In addition, when a vehicle crashes during its running operation, the upper body of the driver hits the steering wheel because the driver is forwardly bent by inertial force, or hits a steering shaft engaged to the steering wheel that is upwardly moved toward the driver. In order to overcome the above problems, an impact absorption structure capable of absorbing impacts applied to the driver's knee is provided in the steering column coverre.
As an example of the impact absorption structure, according to the Korean utility model laid-open No. 1998-045194, there is provided an impact absorption apparatus of a vehicle steering column cover. An impact absorption shell formed of a buffering material is provided in an inner surface of a steering column cover corresponding to a position of a driver's knee for thereby effectively absorbing a direct impact with the steering shaft. When a vehicle crashes, the impact absorption shell installed in an inner surface of the steering column cover is deformed for thereby absorbing impact energy based on the deforming structure. The time from when the driver's knee crashes with the steering column cover to when the impact is actually applied is decreased for thereby decreasing the impact force.
However, in the conventional impact absorption structure of the steering column cover, when a driver's chest crashes with the steering wheel, the impact may be transferred to the steering column cover. In this case, the steering column cover is not deformed because it has a rigid structure. Namely, the conventional impact absorption structure of the steering column cover is designed to absorb only the impact applied to the driver's knee. There is not any method for absorbing the impact applied to the driver's chest.
In addition, according to the Japanese patent No. Hei 2-200570, there is provided a column cover in which the strength of the upper side of the cover is smaller than the strength of the lower portion of the cover. In the above patent, there is not any method for absorbing the impact applied to the driver's chest.
According to the Japanese patent laid-open No. Hei 6-247321, enhancement of an impact absorption is effected by changing the inner structure of the cover. A first impact absorbent and a second impact absorbent are provided in the interior of the cover. When a certain impact is applied, the first impact absorbent is destroyed, and then the second impact absorbent is destroyed thereby enhancing the ability to absorb the entire impact energy. In addition, according to the Japanese patent open laid-open No. Hei 6-298101, the cover is divided into the upper portion and the lower portion. The lower portion is fixed to the steering column bracket. A central shaft portion formed in the interior of the upper portion is combined with a central cylindrical portion formed in the interior of the lower portion, so that the upper portion is fixed to the lower portion.
However, in the above constructions, it is possible to enhance an impact energy absorption rate based on the structural characteristic of the cover, but the structures are so complicated.